Video communications systems are continually being enhanced to meet requirements such as reduced cost, reduced size, improved quality of service, and increased data rate. Many advanced processing techniques can be specified in a video compression standard. Typically, the design of a compliant video encoder is not specified in the standard. Optimization of the communication system's requirements is dependent on the design of the video encoder. An important aspect of the encoder design is rate control.
The video encoding standard H.264 utilizes a combination of intra-coding and inter-coding. Intra-coding uses spatial prediction based on information that is contained in the picture itself. Inter-coding uses motion estimation and motion compensation based on previously encoded pictures.
For all methods of encoding, rate control can be important for maintaining a quality of service and satisfying a bandwidth requirement. Instantaneous rate, in terms of bits per frame, may change over time. An accurate up-to-date estimate of rate must be maintained in order to control the rate of frames that are to be encoded.
Limitations and disadvantages of conventional and traditional approaches will become apparent to one of ordinary skill in the art through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.